Viral Hepatitis

Hepatitis describes inflammation in the liver. There are five types of viral hepatitis. 

All viral hepatitis infections are notifiable diseases. The UK Health Security Agency need to be notified of all cases. 

Other Causes of Hepatitis

Other causes of hepatitis include:

• Alcoholic hepatitis
• Non-alcoholic steatohepatitis (NASH)
• Autoimmune hepatitis
• Drug induced hepatitis (e.g. paracetamol overdose)

Presentation

Viral hepatitis may be asymptomatic or present with non-specific symptoms of:

• Abdominal pain
• Fatigue
• Flu-like illness
• Pruritus (itching)
• Muscle and joint aches
• Nausea and vomiting
• Jaundice 

Liver Function Tests

A “hepatitic picture” on liver function tests refers to high transaminases (AST and ALT) with proportionally less of a rise in ALP. Transaminases are liver enzymes released into the blood due to inflammation of the liver cells.

Bilirubin can also rise as a result of inflammation of the liver cells. High bilirubin causes jaundice.

Hepatitis A

Hepatitis A is the most common viral hepatitis worldwide but relatively rare in the UK. It is an RNA virus transmitted via the faecal-oral route, usually in contaminated water or food. Vaccination is available to reduce the chance of developing the infection. It can cause cholestasis (slowing of bile flow through the biliary system), with pruritus, significant jaundice, dark urine and pale stools. 

Diagnosis is based on IgM antibodies to hepatitis A. It usually resolves without treatment. Rarely it can lead to acute liver failure (fulminant hepatitis). Management is supportive, with basic analgesia.

Hepatitis B

Hepatitis B is a double-stranded DNA virus. It is transmitted by direct contact with blood or bodily fluids, such as during sexual intercourse or sharing needles (e.g., IV drug users or tattoos). It can also be passed through sharing toothbrushes, razors or contact with open cuts. It can be passed from mother to child during pregnancy and delivery (known as vertical transmission).

Most people fully recover from the infection within 1-3 months. However, 5-15% become chronic hepatitis B carriers. In carriers, the virus DNA has integrated into the cell nucleus. They continue to produce viral proteins.

Antibodies are produced by the immune system against pathogen proteins. Antigens are proteins that are targeted by the antibodies. Antibodies are part of the immune system. Antigens are part of the virus.

There are key viral markers to remember with hepatitis B:

• Surface antigen (HBsAg) – active infection
• E antigen (HBeAg) – a marker of viral replication and implies high infectivity
• Core antibodies (HBcAb) – implies past or current infection
• Surface antibody (HBsAb) – implies vaccination or past or current infection
• Hepatitis B virus DNA (HBV DNA) – a direct count of the viral load

Screening for hepatitis B involves testing for HBcAb (for previous infection) and HBsAg (for active infection). When these are positive, further testing is performed for HBeAg and viral load (HBV DNA).

HBsAb demonstrates an immune response to HBsAg. The HBsAg is given in the vaccine, so having a positive HBsAb may indicate they have been vaccinated and created an immune response. The HBsAb may also be present in response to an infection. The other viral markers are necessary to distinguish between the presence of HBsAb due to previous vaccination and infection.

HBcAb can help distinguish acute, chronic and past infections. We can measure IgM and IgG versions of the HBcAb. IgM implies an active infection and will give a high titre with an acute infection and a low titre with a chronic infection. IgG indicates a past infection where the HBsAg is negative.

HBeAg correlates with infectivity. Where the HBeAg is present, it implies the patient is in the acute phase of infection, where the virus is actively replicating. When the HBeAg is high, they are highly infectious to others. When the HBeAg is negative, but the HBeAb is positive, this implies they have been through a phase where the virus was replicating but has now stopped replicating and are less infectious.

Vaccination is available and involves injecting the hepatitis B surface antigen (HBsAg). Vaccinated patients are tested for HBsAb to confirm their response to the vaccine. The vaccine requires 3 doses at different intervals. Vaccination for hepatitis B is included as part of the UK routine vaccination schedule (as part of the 6-in-1 vaccine).

Management of hepatitis B involves:

• A low threshold for screening patients at risk of hepatitis B
• Screen for other viral infections (e.g., HIV, hepatitis A, C and D)
• Referral to gastroenterology, hepatology or infectious diseases for specialist management
• Avoid alcohol 
• Education about reducing transmission 
• Contact tracing and informing potential at-risk contacts
• Testing for complications (e.g., FibroScan for cirrhosis and ultrasound for hepatocellular carcinoma)
• Antiviral medication can be used to slow the progression of the disease and reduce infectivity
• Liver transplantation for liver failure (fulminant hepatitis)

Hepatitis C

Hepatitis C is an RNA virus. It is spread by blood and body fluids (e.g., semen). No vaccine is available. Hepatitis C is now curable with direct-acting antiviral medications (e.g., sofosbuvir and daclatasvir).

Without treatment:

• 1 in 4 fight off the virus and make a full recovery
• 3 in 4 develop chronic hepatitis C

Complications of hepatitis C include:

• Liver cirrhosis and associated complications of cirrhosis 
• Hepatocellular carcinoma

Testing involves:

• Hepatitis C antibody is the screening test
• Hepatitis C RNA testing is used to confirm the diagnosis of hepatitis C, calculate the viral load and identify the genotype

Management involves the same general principles as hepatitis B (described above).

Antiviral treatment with direct-acting antivirals (DAAs) is tailored to the specific viral genotype. They successfully cure the infection in over 90% of patients. The duration of treatment is typically 8 to 12 weeks.

Hepatitis D

Hepatitis D is an RNA virus. It can only survive in patients who also have a hepatitis B infection. It attaches itself to the HBsAg and cannot survive without this protein. There are very low rates in the UK. Hepatitis D increases the complications and disease severity of hepatitis B. 

Hepatitis D can be treated with pegylated interferon alpha over at least 48 weeks. This treatment is not very effective and has significant side effects.

Hepatitis E

Hepatitis E is an RNA virus transmitted by the faecal-oral route. It is very rare in the UK. It usually produces only a mild illness, the virus is cleared within a month, and no treatment is required. Rarely it can progress to chronic hepatitis and liver failure, usually in immunocompromised patients. There is no vaccination.

Last updated May 2023